Saturday, March 14, 2015

A Butterfly's Colourful Camouflage Helps It Avoid Hungry Predators

The Natural World


Paper Kite Butterflies: “The sheen of these gold chrysalides offers a shield of camouflage
for paper kite butterflies growing inside them.”
Photo Credit: Michael Weber, imageBroker/Corbis
Source
: NatGeo

An article, by Liz Langley, in National Geographic examines why butterflies have such striking colours; take the paper kite butterfly (Idea leuconoe) as a fine example.

Langley writes:
The paper kite butterfly, native to Asia, is light yellow or off-white with an elaborate pattern of swooping black lines and dots. But its chrysalis—a hard case that protects the caterpillar during its final transformation into a butterfly—is a shiny, golden hue.It’s unknown why the chrysalis itself is gold, but its shininess helps camouflage the developing butterfly, says Katy Prudic, a biologist at Oregon State University in Corvallis.

In particular, the sheen is “disruptive” to potential predators—it makes the chrysalis “hard to detect in a complicated background,” Prudic says. A hungry bird may even think it looks like a drop of water.
Camouflage is crucial to chrysalides: Because growing butterflies are unable to move and in danger of being eaten or parasitized, “they're a sitting duck,” Prudic notes.

The giant swallowtail is another example of chrysalis camo. In that species, the chrysalis resembles part of the tree on which it hangs—or it looks a bit snakelike, depending on the vantage point. (Watch video: Growing Up Butterfly.)
This species' caterpillar has some tricks up its sleeve: It can resemble bird droppings but can also look like a tiny snake at a later stage of development.

The monarch butterfly chrysalis has what appear to be gold dots and threads, which help the developing insect blend in with leaves.

Female Monarch Butterfly: “The monarch butterfly (Danaus plexippus) is a
milkweed butterfly
(subfamily Danainae) in the family Nymphalidae. It may be the most
familiar North American butterfly. Its wings feature an easily recognizable orange and black
pattern, with a wingspan of 8.9–10.2 cm (3½–4 in),” Wikipedia says.
Photo Credit
: Kenneth Dwain Harrelson; May 29, 2007
Source: Wikipedia


Camouflage is an adaptive method, no doubt, that ensures that a particular species survives from being eaten by its natural predators.The list is long, and includes wasps, frogs, lizards and monkeys.The monarch butterfly (Danaus plexippus) has another adaptive mechanism, in addition to camouflage, that protects it to a large degree from being eaten. Monarchs taste bad, a result of caterpillars consuming milkweed before metamorphosing into butterflies.

One butterfly website says that this gives monarchs a chemical defence: “[T]hey sequester the poisonous cardenolides (also called cardiac glycosides) in the milkweed. Cardenolides are poisonous to vertebrates.” The bright colours (yellow, orange, black, and white) of the monarch also act a signal to potential predators that it has these chemical defences. There are predators, though, that can bypass the monrach’s chemical defences: two species of birds, the black-headed grosbeak, the black-backed oriole, and one species of mouse, the black-eared mouse.

I do not see as many monarchs as I used to in my childhood. I saw only a handful of monarchs in parks and at the botanical gardens last year; besides natural predators, monarchs face changes to their winter habitats in Mexico and a reduction in their food supply here in Canada and in the U.S. The World Wildlife Fund Canada says on its website:
Monarch butterflies are currently facing three major risks: illegal logging, lack of milkweed plants and climate change. WWF’s 2013-14 report from Mexico showed that the number of monarch butterflies wintering there was at its lowest in 20 years. This finding was determined by measuring the amount of forest they occupy; in 2013, the number of butterfly acres decreased to 1.65 acres compared to 27.5 acres in 2003.
There might be a way to increase the population of monarch butterflies that would make both human developers and the many butterfly lovers happy. Co-existence has an important place in the realm of ideas, both in the sciences and in the arts. It is not a matter of keeping the natural world pristine [see Primitivism], but of maintaining it to a sufficient degree as to not harm humans. This includes the appreciation of beauty and nature, a Wordsworthian idea, perhaps, but nevertheless steeped in longing and pleasures of the human kind [see Romanticism].

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For more, go to [NatGeo]
nakes, toads, rats, lizards, dragonflies and even monkeys!  - See more at: http://www.thebutterflysite.com/what-eats-butterflies.shtml#sthash.5gIoT8aD.dpuf
nakes, toads, rats, lizards, dragonflies and even monkeys!  - See more at: http://www.thebutterflysite.com/what-eats-butterflies.shtml#sthash.5gIoT8aD.dpuf
Some of the common predators of butterflies include but are certainly not limited to: wasps, ants, parasitic flies, birds, snakes, toads, rats, lizards, dragonflies and even monkeys!  A few of the other animals that are constantly adding butterflies onto their menu list are frogs and spiders. - See more at: http://www.thebutterflysite.com/what-eats-butterflies.shtml#sthash.cuN3py8l.dpuf
Some of the common predators of butterflies include but are certainly not limited to: wasps, ants, parasitic flies, birds, snakes, toads, rats, lizards, dragonflies and even monkeys!  A few of the other animals that are constantly adding butterflies onto their menu list are frogs and spiders. - See more at: http://www.thebutterflysite.com/what-eats-butterflies.shtml#sthash.cuN3py8l.dpuf

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